Oil purifying system



Dec- 12, 1939- R. c. osTr-:RsTRo M Re. 21,299

OIL PURIFYING SYSTEM Original Filed Feb. 18, 1930 Ressuecl Dec. 12, 1939 UNITED STATES PATENT OFFICE oIL PURIFYING SYSTEM poration of Ohio Original No. 1,891,109, dated December 13, 1932,

Serial No. 429,303, February 18, 1930. Application for reissue December 11, 1934, Serial '7 Claims.

This invention relates to the art of purifying or refining hydrocarbon oils, and has specific reference to an improved method for treating hydrocarbon oils which contain undesirable compounds, such as gum-forming and color-imparting bodies and to a new treatment involving the heating of the oil when in the presence of a contact or catalytic material, whereby to separate effectively the undesirable compounds from the purified or treated oils.

In accordance with the present invention this object is attained by passing the oils to be treated in a continuously moving stream through a heating still in the presence of a catalyst such as fullers earth and therein heating the oils while under superatmospheric pressures to high temperatures, whereby to produce polymerization of the undesired compounds in the oils so that through subsequent fractionation such polymerized oils, which have high boiling points, may be removed from the lower boiling desired oils.

It is an outstanding feature of the present invention to provide for the cyclic return of the fullers earth or of the catalyst to the treating zone in order that said catalyst may be used repeatedly in the operation of the system.

In accordance with the present invention, I have found that a treating agent such as fullers earth possesses effective catalytic properties after a single passage thereof through the treating zone, particularly after the catalyst or treating agent, prior to being re-introduced into the treating zone, is brought into Contact With the fresh charging stock. Such a charging stock appears to possess solvent properties by which the adsorbed or polymerized compounds present in the treating agent are removed so thatv said treating agent will be reactivated for operation in the treating zone. In this connection I have also found that the polymerized or undesired oils if l re-introduced into the treating zone possess catalytic activity in furthering polymerization reactions in the stock initially undergoing treatment and in the preferred operation of my system I return a certain percentage of the polymerized oils together with the fullers earth or other treating agent to the heating zone.

By this method of operation I provide for the full revivincation of the catalyst or treating agent and the purifying of the oil in a treating process of this character to the end of effecting a direct economy in the consumption of the treating agent, the cost of which being a Very important item in a process of this character.

For a further understanding of this invention reference is to be had to the following description and the accompanying drawing, in which:

The figure is a diagrammatic View showing one arrangement of apparatus suitable for use in the practice of my invention. This figure is provided with legends and other features adapting it to serve also as a flow sheet.

The numeral l designates a tank adapted for the reception of an untreated mineral oil. Leading from the tank I is a pipe line 2 in which is located a high pressure pump 3 by which the oil under treatment is forced through the coil 4 of the heating still 5. Entering the inlet side of the pump 3 is a pipe line 6 through which is passed or drawn a treating agent, which in this instance consists of What may be termed a fluid mixture of fullers earth and liquid oil, the latter consisting of a high percentage of high boiling products obtained by the cyclic operation of the system. Also connected with the pipe line 2 is a clay feeding unit 'l which is under ready control for the purpose of regulating the input of fresh fullers earth into the system, as such additional quantities of earth are required. The amount of fresh clay added to the system is, of course, much less than that in earlier systems wherein no recirculation of the treating agent is provided.

Within the tube still 5 the oils obtained from the tank I and also the treating agent are subjected to temperatures above the vaporizing temperatures of the oils under treatment, for example 650 F. to 700 F., vaporization of the oils however being prevented by the employment of super-atmospheric pressures suiciently high to maintain the oil in the liquid phase. These pressures Will, of course, vary in accordance with the operating temperatures applied to the oils in the still. While the oils are maintained in this highly heated condition and in the liquid phase they react freely with the finely divided fullers earth present therein to permit of the subsequent separation of the undesirable compounds from the desired compounds present in the oil undergoing treatment. In all probability the heating of the oils to a high temperature Without Substantial cracking thereof While the cils are maintained in the liquid phase and in the presence of the treating agent effects polymerization of the undesirable gum-forming and color-imparting bodies or again the undesirable bodies may be adsorbed by the treating agent. The fullers earth may serve as a catalyst in promoting polymerization reactions or it may be considered an adsorbent.

From the pipe still 5 the treated oils pass by Way of a pipe line 8 to a separator 9. The line 8 contains a pressure relief valve I0 so that the oils in the separator 9 are permitted to freely expand in order that there may take place an effective separation of the heavy clay containing undesirable compounds as liquids from the desired low boiling compounds in the form of vapors. The latter remain in the vapor phase and pass overhead from the separator to a Very large extent free from the higher boiling undesirable compounds. These vapors pass through a line Il to a standard fractionating tower l2. In this tower the vapors are subjected to fractionation in order to remove from the vapors all the entrained undesired higher boiling compounds. These latter compounds collect as a liquid in the bottom of the fractionating tower and may be returned to the top of the vaporizer by the pipe I3, Where they are employed to scrub the vapors passing upwardly through the separator. A pipe line I4 leads from the top of the tower to a condenser I5 and thence to a storage tank I6 which receives the treated and purified hydrocarbons.

One of the outstanding features of the present invention resides in collecting the high boiling or undesired liquid oils and clay in the bottom of the separator and then passing this mixture into a storage tank l1 by the employment of the pipe line I8. The bottom of the tank l1 connects with the pip-e line 6 and is suitably valved in order to regulate the return of the clay-oil mixture to the inlet side of the pump 3. The quantity of high boiling oils collected in tank Il as a result of the poiymerizing reaction and subsequent fractionation is sufficient to provide a uid mixture with the clay whereby it can be pumped back to the heating zone. By this arrangement the fullers earth is again returned to the inlet side of the pipe still for re-circulation through the heating Zone thereof in connection withy the fresh charging stock. The excess heavy oil and clay materials which accumulate in the tank Il are removed by way of the pipe lines I9 and passed preferably through a filter 2i) in order to eiect the separation of the clay or fullers earth in cake-like form from the liquid oils, the clay-free liquid oils are then transferred to a storage tank 2|.

The system as above described has the advantage over prior systems in the matter of providing for complete separation of the undesired compounds from the oil undergoing treatment in order that the purified oils will possess the desired color and freedom from other injurious compounds, and especially is the invention described an improvement on earlier systems by the cyclic circulation of the treating agent. This step results in reducing the quantity of clay or other corresponding treating agent necessary to effect a given degree of purification of the oils undergoing treatment. Instead of eliminating the clay from the system at the end of each complete operation I have provided for its reuse or recirculation. I-Ieretofore such a treating agent as fullers earth has been removed at the end of each operation as, for example by a filter press,

' dried and then burned to restore its effectiveness as a catalyst. I have found, however, that by combining the treating agent with thefresh entrained stock such burning or revivification of the treating agent is not required, and this discovery has made the present invention of greater advantage commercially over the earlier and socalled once through systems of purification.

The present invention is a continuation in part of my prior application Serial Number 405,251,

iiled November 6, 1929, and distinguishes from said prior application by the fact that the oils in the treating Zone are maintained in the liquid phase by the employment of super-atmospheric pressures instead of being permitted to vaporize as set forth in said application.

What is claimed is:

1. The method of removing gum-forming and color-imparting bodies from cracked low boiling petroleum oils containing large quantities of unsaturated hydrocarbons which comprises: heating a confined flow-stream composed of such an oil and a finely divided solid treating agent in a heating zone to a temperature above the vaporization point of the oil while applying pressure to the stream to prevent substantially the evolution of voil vapor, maintaining said flow stream in said zone under said conditions of temperature and pressure for a sufficient period of time to effect polymerization of the undesired hydrocarbons, then passing the flow-stream under materially reduced pressures through a vaporizing zone maintained at a temperature to keepin a vaporous state the desired treated oils and separate therefrornl higher boiling polymerized oils and said treating agent, and returning a portion, at least, of said polymerized oils and treating agent to said heating zone for repassage through said heating zone in admixture with fresh oils.

2. The method of treating cracked low boiling petroleum oils containing `high percentages of unsaturated hydrocarbons to remove objectionable gurn-forming and color-imparting bodies therefrom which comprises: continuously heating a confined flow-stream composed of such an oil and a finely divided solid treating agent during passage through a heating zone to a temperature above the vaporization point of the oil and below a temperature wherein any substantial cracking of the oil takes place, coincidentally applying pressure to the flow-stream, during passage thereof through said heating zone to maintain the flow-stream substantially in the liquid phase, maintaining said mixture in said zone under said conditions of temperature and pressure for a suiiicient period of time to eiect polymerization of the more highly reactive unsaturated hydrocarbons, then passing the flow-stream under materially reduced p-ressures through a vaporizing zone maintained at a temperature to keep in a vaporous state the desired treated oils and separate therefrom higher boiling polymerized oils and said treating agent, and returning a portion, at least, of said polymerized oils and treating agent to said heating zone for repassage through said heating zone in admixture with fresh oils.

3. The method of decolorizing and degumming low boiling cracked petroleum oils which comprises: continuously heating a conned iiowstream composed of such an oil and a iinely divided solid treating agent during passage thereof through a heating zone to a temperature above the vaporization point of the oil but not sufficiently high to appreciably crack the same, coincidentally applying pressures to the now-stream while in said heating zone to maintain the same substantially in the liquid phase, maintaining said mixture in said zone under said conditions of temperature and pressure for a suicient period of time to effect polymerization of the more highly reactive unsaturated hydrocarbons, removing the How-stream from said heating zone and passing the same under reduced pressures into a vaporizing zone, removing from the upper portion of said vaporizing zone in a vaporous state the desired oils, fractionating the vapors of said oils to remove entrained high boiling liquids, condensing and collecting said desired vapors, separately removing from said vaporizing Zone the high boiling polymerized oils formed in said heating zone and said treating agent, and passing a portion, at least, of the polymer treating agent fraction to the flow-stream of fresh oil entering the heating zone.

4; A process for removing gum-forming and color-imparting bodies from cracked low boiling petroleum oils which comprises: passing a conned now-stream composed of an oil to be treated and a iinely divided solid treating agent through a heating zone and heating the oils of said now-stream to a temperature above the Vaporization point thereof but below a temperature at which material cracking of the oil Will be effected, maintaining said iloW-stream during its passage through said heating zone under pressures sufficiently high to keep the oils of said stream in substantially the liquid phase, retaining saidl mixture in said Zone under said conditions of temperature and pressure for a sufcient period of time to eifect polymerization of the more highly reactive unsaturated hydrocarbons, reducing the pressure on the now-stream immediately upon its discharge from the heating zone to permit of the free evolution of oil Vapor in a vaporizing zone, separating in said vaporizing Zone vapors of the desired low boiling oils from a fraction composed of high boiling polymerized oils containing said objectionable constituents and treating agent, fractionating, condensing and collecting the vapors of the treated oils discharged from said vaporizing Zone, separately collecting in a storage zone, the high boiling polymerized oils and treating agent, and returning a portion of said polymerized oils and treating agent to the heating zone for repassage through the latter While in an admixed condition with the oils comprising said now-stream.'

5. The method of treating raw gasoline distillates which consists in forming a mixture of the distillates and the treating material comprising a solid, iinely divided adsorbent, heating said mixture under suii'icient pressure to maintain the oil material in the liquid phase and for a period and at a temperature sufficient tobring about substantial improvement of the oil material, and releasing the pressure and distilling off the oil fractions and admitting the vapor produced to a fractionating column and leading fractions from said column to a condenser and adding the residue from said column to the mixture of raw .distillate and treating material about to be heated.

6. The method of treating raw gasoline distillates which consists in forming a mixture of the distillates and the treating material comprising a solid finely divided adsorbent, heating said mix- `ture'under sufficient pressure to maintain the oil material in the liquid phase and for a period and at a temperature suflicient to bring about substantial improvement of the oil material, releasing the pressure and distilling off theoil fractions, admitting the vapor thus produced to a fraotionating column, leading uncondensed fractions from said column to the condenser and adding at least a part of the residue from said column to the mixture of raw distillate and treating material about to be heated.

7. The method of treating raW gasoline distillates which consists in forming a mixture of the distillates and a treating material comprising a solid finely divided adsorbent, heating said mixture under sufcient pressure to maintain a substantial portion of the oil material in the liquid phase to aid in carrying said adsorbent and for a period and at a temperature sufficient to bring about substantial improvement of the oil material, releasing the pressure and distilling oi the oil fraction, admitting the vapor thus produced to a fractionating column, leading uncondensed fractions from said column to a condenser, and adding the residue from said column to the mixture of raw distillate and treating material about to be heated.

RUDOLPH C. OSTERSTROM. 

